The code snippets don't correspond to each other. value 2 doesn't match /update\s*[table\s*]rmdb_dbo./i'. Moreover, the string 'table in the square brackets seems like a meaningful word, but square brackets introduce character classes, so [table\s*] in fact matches a single character a, b, e, l, t, asterisk, or whitespace.

Try to post runnable code like the following:

#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

my %h = (
    'connection-id0' => {
        username1 => ['value 1', 'value 2'],
        username2 => [ 'value5' ],
    },
    'connection-id1' => {
        username1 => ['value 2', 'value 3'],
    },
    'connection-id2' => {
        username1 => ['value 3', 'value 4'],
    }
);
for my $connection (keys %h) {
    foreach my $userid (keys %{ $h{$connection} }) {
        my @ar = @{ $h{$connection}{$userid} };

        if (lc $userid eq 'username1') {
            say "@ar" if grep /value 2/i, @ar;
        }
    }
}
[download]

I used grep so the "value 2" might be located anywhere in the array.